Is BIG BATTERY full of Crap??

[Hedges]

... but it sounds like a cool car ...

I'm afraid "cool" doesn't quite capture it.

 

[Will Prowse]

Maybe the strands are so thin that I can't tell, but I don't see any copper. Even if they were copper, wouldn't 175 amps over 12 feet of 6awg wire be pushing the limits, and potentially unsafe? Or is it the 200C rating that makes it okay?View attachment 26969

Yeah, its copper. I know this picture makes it look like aluminum, but it's not. I have all 3 of their cable sets and I just checked them now at the crimps, and they are copper. I highly doubt anyone would make an aluminum wire with this type of insulation. The 200C insulation is the good stuff. And I also just verified with my cable sets that they are all using 200C rated insulation as I remember.

Oh right, do not push 175A with these cables. They might be able to handle it actually. 200C insulation can allow the conductor to push some large current numbers, but the resistance will go up. It is preferable for high surge applications. My initial application of this type of wire was for my race drones. I would push 100A+ through 12-10 gauge wire. It was unreal. It was for a few seconds only, but it did not melt. Those were large hexacopters with 75C discharge rate lipoly batteries. Really crazy stuff.

 

[Luthj]

The issue with 200C insulation, but small cables, is that while the insulation may handle the temperature rise, the devices at the terminations may not. Many breakers and relays rely on the cable to cool them by conducting heat away. Also, at 200C the the wire retaining methods (zip ties etc) may decided to melt, as could any plastic in contact with the insulation.

6awg at 6ft would be dropping at least half a volt when connectors are counted at 175A.

 

[DKyleM18]

@Will Prowse Thank you for the information. I'm still glad I made my own thicker wire connections, but I feel bad for calling out BigBattery like I did.

 

[Picasso]

If you want to see crazy power in a cable look at the v3 tesla superchargers. the bus bar the cable connects to is water cooled to pull heat out of the cable/connector.

 

[Dzl]

Maybe the strands are so thin that I can't tell, but I don't see any copper. Even if they were copper, wouldn't 175 amps over 12 feet of 6awg wire be pushing the limits, and potentially unsafe? Or is it the 200C rating that makes it okay?

@Will Prowse Thank you for the information. I'm still glad I made my own thicker wire connections, but I feel bad for calling out BigBattery like I did.

Higher insulation temperature rating increases Ampacity rating (safe current carrying capacity of the wire) but cannot help voltage drop or power loss (efficiency / losses due to resistance in the wire).

Vdrop = IR (where R is based on the type of metal, the cross section of the wire and the length of the wire)
Ploss = I²R


For 12ft of 6AWG copper (someone please correct me if I've done the math wrong, I'm still not very confident in my baility to do it correctly):

Vdrop = 175A x (0.0004 x 12ft)
      = 0.84V Voltage Drop
      
Ploss = 175A² x (0.0004 x 12ft)
      = 147W Power Loss
      
      
At Mid SOC (13.2V) that is:
      Voltage Drop = 6.4%
      Power Loss   = 6.4%

As for Ampacity:
According to the ABYC, 6AWG copper wire with 200*C insulation is rated to 135A at upto 50*C / 120*F ambient. The NEC is a bit more liberal allowing 165A for the same type of wire at an ambient of 40*C / 105*F, or 170A at 30*C ambient (if I have done the calculations correctly)

 

[Just John]

I just need to buy a freezer and cycle them a few times. Then we will know.

My understanding is that lithium plating would show up in a capacity test result after a single cycle.

I will buy the coldest freezer I can find.

I see they are now 50 years old, which would mean when I first used them they were 10 years old. We used the Tenney Jr in a computer manufacturing and test lab, and much bigger custom chambers for manufacturing burn in testing.
Tenney Jr
Apparently they also make custom battery test chambers, but explosion proof might be a bit expensive.
Tenney battery test chambers

I think most of us would be happy with zero degrees Fahrenheit testing. I can tell you from personal experience if you open an environmental test chamber that is -50 degrees Celsius, it will snow inside.

 

[Just John]

Do you automate test equipment operation? (Labview, VEE, Python, Matlab, Basic, whatever)

A man after my own heart! Of course when I started automating tests it was in assembler on a Z80 S100 bus system with a GPIB interface (had to write the drivers for that too).

 

[MrGreen]

I honest to God hate it when companies like BigBattery try to throw something out there that on the surface is technically correct BUT the way they are doing it is BULLSHIT. SOOOOO now we are going to have this damn conversation - again - for the second year running - about charging while below freezing ... YES you can do it - YES you can EASILY ruin your battery if you do it wrong -- YES you are charging at a barely minimal rate and NO these batteries will NOT recharge 100 or 50 or 20 or even 10% the next day ... SOOOO what pisses me off is that good people - these guys that live in the cold - in RV's and Tiny homes are going to run out and buy these batteries because BigBattery marketing department tried to get "cretive" in their advertising and the consumer now erroneously thinks that they can fully recharge their batteries below freezing to make it through the night and BB knowing that 99.99% of the ppl out there do not understand the difference between 2C and 0.1Ca ....

Hello @ghostwriter66,

To clarify,

• All marketing material had been fixed within (24) hours of bringing this to our attention.
• The (67) Units set to cut-off at (-5C) have been recalled and recalibrated for said customers.
• We covered all Shipping Costs & Labor Costs - and provided a $100 Credit to all customers for their inconvenience.
• The 600+ Units that are going out now are set to cut-off at (-0C)
• Will Prowse released a video over the weekend showing that the battery in fact charged/discharged @ as low as (-30C) (However we do not recommend this.)
• Please feel free to eMail me at Eric@BigBattery.com if you would like to see a video of the low-temp cut-off testing process.
  
  Thank you for your feedback. Our customers and our #1 Concern and I want to make sure that anyone whom purchase' from BigBattery.com is happy with their battery pack. I am open to any suggested changes and would love to hear your feedback so that we can make better product and serve our customers to the best of our ability. Thank you!

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

Not defending Big Battery, but they are *not* a R&D house. They're in the business of inventory turnover. However, if they prepared the datasheets without verifying the specs, it would be irresponsible (& may even be criminal). They're very likely repeating what their unscrupulous suppliers have told them. VW, Theranos and so many others have done it. It's ultimately the consumers responsibility to vet these claims - not an easy task.

@fat_old_sun,
Our data sheets are accurate, it was a mistake by our marketing dept. which was swiftly corrected. On (67) Units - our BMS was set to cut-off at (-5C), these batteries were taken back and recalibrated to low-temp cutoff at (-0C). All future batteries are set to Low-Temp Cut-Off at (-0C).
Although not advised, I believe Will Prowse brought our battery down to (-30C) and it still functioned - Although we do not recommend taking it down past (-0C) and our BMS will cut-off on all mass-produced packs at (-0C).

Thank you for your concern, I really appreciate the feedback we receive from this forum. We are always striving to get better and the input provided here does not fall on deaf ears. You guys are awesome, Thank you for your help!

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

I am going to freeze those cells to -20C, and charge at max rate. Repeat. Then capacity test, or test internal resistance with my cell monitor.

And I do not trust any company or distributor. @fat_old_sun is correct, and the only way to find out is to test it ourselves. Bigbattery has a qualified EE as head designer, and he knows his stuff. I am not sure where they found him, but he seems to know everything. I have thrown a lot of questions at him, and he always knows his stuff.

But yeah, lets test it!

@Will Prowse ,

Thank you for your feedback. Your video's help us to become better.

We appreciate your honest reviews and respect you as a leader in this space.

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

@Will Prowse Thank you for the information. I'm still glad I made my own thicker wire connections, but I feel bad for calling out BigBattery like I did.

@DKyleM18,

Thank you for your feedback, we are striving to offer you better products and the guaranteed best prices in the USA. I welcome any constructive feedback so that we can in-fact get better at our mission.

Our goal is to exponentially increase the adoption of more efficient battery technology in the USA, to reach this goal - we are attempting to bring down the price of LI-ION & LFP Technology and make easy to install Lead-Acid Drop-In Replacement Packs.

I really do appreciate you and everyone else on this forum whom help us become better at our mission. Feel free to send any comments that you have to Eric@BigBattery.com so that I may do my best to lead this company in the direction that is best for our customers.

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[ghostwriter66]

Hang in there @MrGreen ... it will get better .... I know its an old joke to most but for a 23 yr old girl from LAX it was new to me and i laughed so hard when I heard it from one of the old wellhands the other day ... but it sort of fits what your going thru ... let see if I can remember it correctly ...

So a man walks into a bar, and sits down. He starts a conversation with an old guy next to him. The old guy has obviously had a few. He says to the man:

"You see that oil rig out there? Built it myself, hand crafted each piece, and it's the best oil rig in town! But do they call me "McGregor the oil rig builder"? No! And you see that bridge over there? I built that, took me two months, through rain, sleet and scorching weather, but do they call me "McGregor the bridge builder"? No! And you see that tower over there, I built that, best tower in the county! But do they call me "McGregor the tower builder"? No!"

The old guy looks around, and makes sure that nobody is listening, and leans to the man, and he says:

"but you fu#k one sheep..."

 

[upnorthandpersonal]

Will Prowse released a video over the weekend showing that the battery in fact charged/discharged @ as low as (-30C) (However we do not recommend this.)

Well, not really. The video showed that the battery could be put in a freezer, taken out in the nice Las Vegas weather, and then charged. This is of course completely different from using said battery in a constant -30C environment. In addition, low temp cut-off did not trigger which means that either a) the sensor failed or b) the battery wasn't at a low temperature at all.

 

[DJSmiley]

@fat_old_sun,
Our data sheets are accurate, it was a mistake by our marketing dept. which was swiftly corrected. On (67) Units - our BMS was set to cut-off at (-5C), these batteries were taken back and recalibrated to low-temp cutoff at (-0C).
Although not advised, I believe Will Prowse brought our battery down to (-30C) and it still functioned - Although we do not recommend taking it down past (-0C) and our BMS will cut-off on all mass-produced packs at (-0C).

Where is the temperature sensor located? Wills test showed it was still charging when the cells when they were at -23C or so.
So either
- The temperature sensor is not placed between the (cold) cells, thus gave a false reading in this specific test (Since the sensor was already warmed up by the ambient temperature), although this is not likely to happen in real life
- The low-cutoff at -5C didn't actually work (why would it work at -0C in that case?)
- The cells weren't completely cold, only on the outer layers since they weren't cooled long enough to fully reach <-5C

 

[MrGreen]

Hang in there @MrGreen ... it will get better .... I know its an old joke to most but for a 23 yr old girl from LAX it was new to me and i laughed so hard when I heard it from one of the old wellhands the other day ... but it sort of fits what your going thru ... let see if I can remember it correctly ...

So a man walks into a bar, and sits down. He starts a conversation with an old guy next to him. The old guy has obviously had a few. He says to the man:

"You see that oil rig out there? Built it myself, hand crafted each piece, and it's the best oil rig in town! But do they call me "McGregor the oil rig builder"? No! And you see that bridge over there? I built that, took me two months, through rain, sleet and scorching weather, but do they call me "McGregor the bridge builder"? No! And you see that tower over there, I built that, best tower in the county! But do they call me "McGregor the tower builder"? No!"

The old guy looks around, and makes sure that nobody is listening, and leans to the man, and he says:

"but you fu#k one sheep..."

I "LOL'd" when I read this.. Thank you @ghostwriter66 : )

Yes, We are going to have to have some thick-skin when reading all of these comments - but (for the most part) I believe they make us better.

We can learn a lot from this Forum (Thanks to Will Prowse) and everyone else who posts our products here. Thank You All! : )

 

[MrGreen]

Well, not really. The video showed that the battery could be put in a freezer, taken out in the nice Las Vegas weather, and then charged. This is of course completely different from using said battery in a constant -30C environment. In addition, low temp cut-off did not trigger which means that either a) the sensor failed or b) the battery wasn't at a low temperature at all.

Hello @upnorthandpersonal ,

The low-temp cut-off does in fact work. Please have anyone test that has received our mass-production. We have sent many video's of this and happy to post them on our YouTube channel as well. As per the (-30C), you are 100% Correct - We do want anyone using our batteries in these environments as they are out of our parameters. Our mass-produced run will cut-off at (-0C) now and the (67) packs that cut-off at (-5C) have been recalled and recalibrated for free while providing those customers with credits for the inconvenience and covering all shipping/labor. We are doing the best we can and hope that no one uses our batteries other than intended.

Thank you for your input. Have a great day! : )

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[ArthurEld]

As per the (-30C), you are 100% Correct - We don't want anyone using our batteries in these environments as they are out of our parameters.

I think you meant don't

 

[JAS]

Our mass-produced run will cut-off at (-0C) now

Can I have a clarification? Does this mean it cuts off charging at 0C or it cuts off operating at 0C?

 

[ghostwriter66]

Can I have a clarification? Does this mean it cuts off charging at 0C or it cuts off operating at 0C?

Going to say that pretty sure that he means cutoff charging .... we operate ours down to -30C - we just don't charge them until they get above 0C ...

 

[Deleted member 9967]

Hang in there @MrGreen ... it will get better .... I know its an old joke to most but for a 23 yr old girl from LAX it was new to me and i laughed so hard when I heard it from one of the old wellhands the other day ... but it sort of fits what your going thru ... let see if I can remember it correctly ...

So a man walks into a bar, and sits down. He starts a conversation with an old guy next to him. The old guy has obviously had a few. He says to the man:

"You see that oil rig out there? Built it myself, hand crafted each piece, and it's the best oil rig in town! But do they call me "McGregor the oil rig builder"? No! And you see that bridge over there? I built that, took me two months, through rain, sleet and scorching weather, but do they call me "McGregor the bridge builder"? No! And you see that tower over there, I built that, best tower in the county! But do they call me "McGregor the tower builder"? No!"

The old guy looks around, and makes sure that nobody is listening, and leans to the man, and he says:

"but you fu#k one sheep..."

Thank you.
Laughed at this one and going to tell others now.

 

[Deleted member 9967]

Hello @upnorthandpersonal ,

The low-temp cut-off does in fact work. Please have anyone test that has received our mass-production. We have sent many video's of this and happy to post them on our YouTube channel as well. As per the (-30C), you are 100% Correct - We do want anyone using our batteries in these environments as they are out of our parameters. Our mass-produced run will cut-off at (-0C) now and the (67) packs that cut-off at (-5C) have been recalled and recalibrated for free while providing those customers with credits for the inconvenience and covering all shipping/labor. We are doing the best we can and hope that no one uses our batteries other than intended.

Thank you for your input. Have a great day! : )

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

Wait, you are paying for shipping BOTH ways?
ok sure.
What are you trying to do?
Show up EVERYONE else? LOL
Because you just did it
Except the overkill guy.

Wow, colour me impressed.

 

[DASH]

I just need to buy a freezer and cycle them a few times. Then we will know.

My understanding is that lithium plating would show up in a capacity test result after a single cycle.

I will buy the coldest free

Those have got to be crazy expensive -20C will do haha

edit: just ordered Midea, which hits -28C. So we can easily trigger the charging protection sensor on the -20C packs.

Great. If You run into a problem getting the temperature low enough, some dry ice would probably do the trick.

 

[DASH]

I am going to freeze those cells to -20C, and charge at max rate. Repeat. Then capacity test, or test internal resistance with my cell monitor.

And I do not trust any company or distributor. @fat_old_sun is correct, and the only way to find out is to test it ourselves. Bigbattery has a qualified EE as head designer, and he knows his stuff. I am not sure where they found him, but he seems to know everything. I have thrown a lot of questions at him, and he always knows his stuff.

But yeah, lets test it!

That should be interesting

 

[DASH]

One thing the above trend makes me think about is how useful it might be to have a charger (or maybe BMS) that 'throttled' current based on temperature as opposed to a simple 'on/off.' Victron controllers have low temp protection (with an addon) and are temperature aware, they also have the ability to manually limit current. It seems like this is all the building blocks for what I'm envisioning, the software would just need to be designed for this.

Some Solar Controllers have a temperature sensor to regulate the amount of charge to the battery, but I believe this is only used on flooded and perhaps AGM batteries.